The value of correctly diagnosing axial spondyloarthritis for patients and society

OBJECTIVE

To demonstrate the value of diagnosing axSpA, by comparing health and costs associated with available diagnostic algorithms and perfect diagnosis.

METHODS

Using data from SPACE and other cohorts, a model was developed to estimate health (quality-adjusted life-years, QALYs) and costs (healthcare consumption and work productivity losses) of different diagnostic algorithms for axSpA amongst patients with low back pain referred to a rheumatologist, over a 60-year horizon. The model combined a decision-tree (diagnosis) with a state-transition model (treatment). The three algorithms (Berlin [BER, highest specificity], Modification 1 [M1; less strict inflammatory back pain (IBP) criterion] and Modification 2 [M2; IBP not mandatory as entry criterion, highest sensitivity]) were compared. Changes in sensitivity/specificity were explored and the value of perfect diagnosis was investigated.

RESULTS

For each correctly diagnosed axSpA patient, up to 4.7 QALYs and €60,000 could be gained/saved, considering a societal perspective. Algorithm M2 resulted in more health and lower costs per patient (24.23 QALYs; €157,469), compared to BER (23.96 QALYs; €159,423) and M1 (24.15 QALYs; €158,417). Hypothetical improvements in M2 sensitivity resulted in slightly more value compared to improvements in specificity. Perfect diagnosis can cost €7,500 per patient and still provide enough value.

CONCLUSION

Correct diagnosis of axSpA results in substantial health and cost benefits for patients and society. Not requiring IBP as mandatory for diagnosis of axSpA (algorithm M2) provides more value and would be preferable. A considerably more expensive diagnostic algorithm with better accuracy than M2 would still be considered good value for money.

Hounsfield Units measured in low dose CT reliably assess vertebral trabecular bone density changes over two years in axial spondyloarthritis

OBJECTIVES

To describe low dose Computed Tomography (ldCT) Hounsfield Units (HU) two-year change-from-baseline values (expressing trabecular bone density changes) and analyse their inter-reader reliability per vertebra in radiographic axial spondyloarthritis (r-axSpA).

METHODS

We used 49 patients with r-axSpA from the multicentre two-year Sensitive Imaging in Ankylosing Spondylitis (SIAS) study. LdCT HU were independently measured by two trained readers at baseline and two years. Mean (standard deviation, SD) for the change-from-baseline HU values were provided per vertebra by reader. Intraclass correlation coefficients (ICC; absolute agreement, two-way random effect), Bland-Altman plots and smallest detectable change (SDC) were obtained. Percentages of vertebrae in which readers agreed on the direction of change and on change >|SDC| were computed.

RESULTS

Overall, 1,053 (98% of all possible) vertebrae were assessed by each reader both at baseline and two years. Over two years, HU mean change values varied from -23 to 28 and 29 for reader 1 and 2, respectively. Inter-reader reliability of the two-year change-from-baseline values per vertebra was excellent: ICC:0.91-0.99; SDC:6-10; Bland-Altman plots were homoscedastic, with negligible systematic error between readers. Readers agreed on the direction of change in 88-96% and on change >|SDC| in 58-94% of vertebrae, per vertebral level, from C3 to L5. Overall, similar results were obtained across all vertebrae.

CONCLUSION

LdCT measurement of HU is a reliable method to assess two-year changes in trabecular bone density at each vertebra from C3-L5. Being reliable across all vertebrae, this methodology can aid the study of trabecular bone density changes over time in r-axSpA, a disease affecting the whole spine.

Role of vertebral corner inflammation and fat deposition on MRI on syndesmophyte development detected on whole spine low-dose CT scan in radiographic axial spondyloarthritis

Objectives

To investigate the associations between MRI detected vertebral corner inflammation (VCI) and vertebral corner fat deposition (VCFD) on whole spine low-dose CT scan (ldCT) detected syndesmophyte formation and growth.

Methods

Patients from the Sensitive Imaging in Ankylosing Spondylitis cohort underwent MRI (baseline, 1 year and 2 years) and ldCT (baseline and 2 years). MR images were scored by three readers for VCI and VCFD, MRI patterns were defined by presence of VCI and/or VCFD over 2 years. LdCT images were scored by two central readers for presence and size of syndesmophytes and change was calculated for new or new/grown syndesmophytes. Multilevel generalised estimated equations were used to test the associations between VCI and VCFD and syndesmophyte development.

Results

Fifty radiographic patients with axial spondyloarthritis were included (mean age 49 years, 86% male, 78% HLA-B27+). Absence of both VCI and VCFD protected against syndesmophyte development (ORs 0.36–0.37). Presence of VCI and/or VCFD increased the risk of syndesmophyte development (ORs 1.73–2.60). Out of all corners with a new or new/grown syndesmophyte, 47% of corners according to reader 1 and 44% according to reader 2 had neither VCI nor VCFD preceding the bone formation.

Conclusions

VCI and VCFD were positively associated with syndesmophyte development. This has been shown for the first time for syndesmophytes detected on ldCT and also in the thoracic spine. However, almost half of all bone formation occurred in corners without VCI or VCFD, suggesting the presence of these lesions in yearly MRIs does not fully clarify the development of syndesmophytes.

Lifestyle Factors and Disease Activity over Time in Early Axial Spondyloarthritis - The SPondyloArthritis Caught Early (SPACE) Cohort

OBJECTIVE

Our aim was to study the importance of baseline Body Mass Index (BMI), smoking and alcohol consumption (AC) for disease activity (DA) over one year in early axial spondyloarthritis (axSpA), stratified by sex.

METHODS

In the SPondyloArthritis Caught Early cohort (patients with chronic back pain for ≥3 months, ≤2 years and onset <45 years), ASDAS was recorded at inclusion, 3 and 12 months. All patients included in the analysis had axSpA based on a high physician's level of confidence at baseline. Differences in ASDAS over 1 year by BMI (normal <25, overweight 25-29.9, obese ≥30 kg/m²), smoking history (never/previous/current) and AC (none, 0.1-2, 3-5, ≥6 units/week) at baseline were estimated using mixed linear regression models.

RESULTS

There were 344 subjects (mean age 30 years; 49% men). In women, obesity was associated with 0.60 (95% CL 0.28, 0.91) higher ASDAS compared to normal BMI. In both sexes, AC tended to be associated with lower DA over one year, with a significant association only in women with the highest AC (mean difference -0.55 (96% CL-1.05, -0.04). Smoking was associated with higher ASDAS over one year compared to never smoking in both sexes, albeit the difference reached statistical significance only in female former smokers. Results were similar in multivariable analysis, adjusted for all lifestyle factors and other confounders.

CONCLUSION

In early axSpA, BMI and smoking are associated with higher DA over one year, and AC with lower DA. The magnitude of the modest associations may differ between men and women.

Development and validation of an alternative ankylosing spondylitis disease activity score when patient global assessment is unavailable

Objective

To develop an alternative Ankylosing Spondylitis Disease Activity Score (ASDAS) to be used in research settings in axial SpA (axSpA) when Patient Global Assessment (PGA) is unavailable in databases.

Methods

Longitudinal data from four axSpA cohorts and two randomized controlled trials were combined. Observations were randomly split in a development (N = 1026) and a validation cohort (N = 1059). Substitutes of PGA by BASDAI total score, single or combined individual BASDAI questions, and a constant value, were established in the development cohort. Conversion factors for each substitute were defined by Generalized Estimating Equations, obtaining seven ‘alternative’ formulae. Validation was performed in the validation cohort according to the OMERACT filter, taking into consideration: (i) truth (agreement with original-ASDAS in the continuous score, by intraclass correlation coefficient and in disease activity states, by weighted kappa); (ii) discrimination [standardized mean difference of ASDAS scores between high/low disease activity states defined by external anchors, e.g. Patient Acceptable Symptom State; agreement (kappa) in the percentage of patients reaching ASDAS improvement criteria according to alternative vs original formulae]; and (iii) feasibility.

Results

Comparing various options, alternative-ASDAS using BASDAI total as PGA replacement proved to be: truthful (intraclass correlation coefficient = 0.98, kappa = 0.90), discriminative [ASDAS scores between Patient Acceptable Symptom State no/yes: standardized mean difference = 1.37 (original-ASDAS standardized mean difference = 1.43); agreement with original-ASDAS in major improvement/clinically important improvement criteria: kappa = 0.93/0.88] and feasible (BASDAI total often available, as questions required for the ASDAS; conversion coefficient ≈ 1).

Conclusion

Alternative-ASDAS using BASDAI total score as PGA replacement is the most truthful, discriminative and feasible instrument.

Facet joint ankylosis in r-axSpA: detection and 2-year progression on whole spine low-dose CT and comparison with syndesmophyte progression

Objectives

To evaluate the occurrence and progression of facet joint ankylosis in the whole spine using low-dose CT (ldCT) in radiographic axial spondyloarthritis (r-axSpA) and compare progression of facet joint ankylosis and syndesmophytes.

Methods

Patients with r-axSpA from the Sensitive Imaging in Ankylosing Spondylitis (SIAS) cohort underwent ldCT at baseline (n = 60) and 2 years (n = 53). Facet joints (right and left, levels C2-S1) were scored as ankylosed, not ankylosed or unable to assess. Joints that were frequently poorly visible (>15% missing), were excluded. Inter-reader reliability on the patient level was assessed with intraclass correlation coefficients (ICCs) and smallest detectable change (SDC). Ankylosis was assessed at joint level and patient level for both timepoints. Syndesmophytes were assessed with CT syndesmophyte score.

Results

Levels C5-T2 were difficult to assess and excluded from all further analyses. Facet joint ICCs were good to excellent for status scores (0.72–0.93) and poor to excellent for progression scores (0.10–0.91). Facet joint ankylosis was detected at every level but most frequently in the thoracic joints. In total, 48% of patients showed 2-year progression. Most progression occurred in the thoracic segment. Using SDCs as cutoff, 18% of patients had progression of facet joint ankylosis only, whereas 20% of patients had progression of syndesmophytes only.

Conclusion

This is the first study evaluating facet joints in the whole spine by ldCT in r-axSpA. Facet joint ankylosis was detected most often in the thoracic spine. Assessing facet joints in addition to syndesmophytes detected substantially more patients with damage progression over two years.

Supervised Group Exercise in Axial Spondyloarthritis: Patients' Satisfaction and Perspective on Evidence-Based Enhancements

OBJECTIVE

Supervised group exercise (SGE) has been proven effective in patients with axial spondyloarthritis (SpA), but its contents and dosage do not always comply with current scientific insight. This aim of this study was to describe axial SpA patients' satisfaction with current SGE and perspective on potential evidence-based SGE enhancements.

METHODS

Patients with axial SpA who participated in SGE in 4 regions in The Netherlands (n = 118) completed a cross-sectional survey on their satisfaction with features of their current SGE (8 questions scored on a 3-point Likert scale; 1 overall grade, scored according to an 11-point scale) and their perspective on the introduction of appropriately dosed cardiorespiratory and strengthening exercise, monitoring of exercise intensity, periodic reassessments, patient education, and supervision by physical therapists with specific expertise (4 dichotomous questions and one 5-point Likert scale).

RESULTS

Most patients were satisfied with the current total intensity (84 of 112 patients [75%]), duration (93 of 111 patients [84%]), and load (89 of 117 patients [76%]) of the program and the proportion of mobility (102 of 114 patients [90%]), strengthening (90 of 115 patients [78%]), and cardiorespiratory exercise (82 of 114 patients [72%]). The median overall grade of the program was a 7 (interquartile range 7-8). Most patients agreed with the implementation of more frequent (home) exercise (73 of 117 patients [62%]), heart-rate monitoring (97 of 117 patients [83%]), and annual reassessments (97 of 118 patients [82%]), whereas 50% agreed with the introduction of patient education (37 of 74 patients). The majority found supervision by therapists specializing in axial SpA to be of high importance (105 of 118 patients [89%]).

CONCLUSION

The majority of SGE participants with axial SpA were satisfied with current SGE but also agreed with enhancements in line with scientific evidence. Current satisfaction levels indicate that a planned implementation strategy, including education and addressing potential barriers and facilitators for the uptake of enhancements, is warranted.

Measuring spinal mobility in early axial spondyloarthritis: does it matter?

OBJECTIVES

To investigate the frequency and order of impairment of spinal mobility measures (SMMs) and their cross-sectional and longitudinal usefulness in early axial spondyloarthritis.

METHODS

SMMs measurements of patients from the DESIR (5-year data) and SPACE (2.6 (1.9) years of follow-up) cohorts were analysed. Cross-sectional (group level) and longitudinal (individual level) analyses were performed comparing SMMs to pre-defined cut-offs derived from healthy individuals. Subgroup analyses were used to study patient and disease characteristics potentially influencing spinal mobility. Reliability was analysed using intraclass correlation coefficients and the smallest detectable change.

RESULTS

In 328 DESIR and 148 SPACE patients, lateral spinal flexion (LSF) and mSchober were the most impaired SMMs. If both (LSF and mSchober) were measured, 84% (DESIR) and 74% (SPACE) of the patients with impairment in ≥1 SMM would be captured. LSF and Bath AS Metrology Index best discriminated between subgroups of patients (higher impairment in patients ever treated with biologics, with higher disease activity and presence of baseline syndesmophytes): e.g. 31% of LSF impairment in patients with Ankylosing Spondylitis Disease Activity Score (ASDAS) < 2.1 in ≥2/3 visits vs 49% in those with ASDS ≥ 2.1. A high variability in SMMs within the same patient over time was observed, even when restricting the analysis to patients with low disease activity. Reliability of SMMs was 'fair' to 'good' (inter-reader intraclass correlation coefficients (2, 1): 0.55-0.84; intrareader intraclass correlation coefficients (2, 1): 0.49-0.72). Smallest detectable changes were in general high, e.g. 5.1 cm for LSF.

CONCLUSION

Cross-sectional use of SMMs, at the group level, is informative in patients with early axial spondyloarthritis. However, the high variation of SMMs over time impairs their use, at the individual patient level.

What is axial spondyloarthritis? A latent class and transition analysis in the SPACE and DESIR cohorts

Objectives

To gain expert-judgement-free insight into the Gestalt of axial spondyloarthritis (axSpA), by investigating its ‘latent constructs’ and to test how well these latent constructs fit the Assessment of SpondyloArthritis international Society (ASAS) classification criteria.

Methods

Two independent cohorts of patients with early onset chronic back pain (SPondyloArthritis Caught Early (SPACE)) or inflammatory back pain (IBP) (DEvenir des Spondylarthopathies Indifférenciées Récentes (DESIR)) were analysed. Latent class analysis (LCA) was used to estimate the (unobserved) potential classes underlying axSpA. The best LCA model groups patients into clinically meaningful classes with best fit. Each class was labelled based on most prominent features. Percentage fulfilment of ASAS axSpA, peripheral SpA (pSpA) (ignoring IBP) or both classification criteria was calculated. Five-year data from DESIR were used to perform latent transition analysis (LTA) to examine if patients change classes over time.

Results

SPACE (n=465) yielded four discernible classes: ‘axial’ with highest likelihood of abnormal imaging and HLA-B27 positivity; ‘IBP+peripheral’ with 100% IBP and dominant peripheral symptoms; ‘at risk’ with positive family history and HLA-B27 and ‘no SpA’ with low likelihood for each SpA feature. LCA in DESIR (n=576) yielded similar classes, except for the ‘no-SpA’. The ASAS axSpA criteria captured almost all (SPACE: 98%; DESIR: 93%) ‘axial’ patients, but the ‘IBP+peripheral’ class was only captured well by combining the axSpA and pSpA criteria (SPACE: 78%; DESIR: 89%). Only 4% of ‘no SpA’ patients fulfilled the axSpA criteria in SPACE. LTA suggested that 5-year transitions across classes were unlikely (11%).

Conclusion

The Gestalt of axSpA comprises three discernible entities, only appropriately captured by combining the ASAS axSpA and pSpA classification criteria. It is questionable whether some patients with ‘axSpA at risk’ will ever develop axSpA.

Top-Ten Tips for Effective Imaging of Axial Spondyloarthritis

Axial spondyloarthritis (axSpA) is a chronic inflammatory condition that encompasses ankylosing spondylitis as well as nonradiographic axSpA and can lead to chronic pain, structural damage, and disability. The disease is strongly associated with the presence of human leukocyte antigen-B27. Early diagnosis of axSpA is significant due to new treatment regimens leading to reduction of inflammation and potentially delaying disease progression. Imaging of the sacroiliac joints and the spine plays an important role in the early diagnosis of spondyloarthritis. In the current review, the top-ten tips for the effective imaging of axSpA are presented to help both radiologists and rheumatologists in using imaging properly and effectively in their clinical practice.

Do ethnicity, degree of family relationship, and the spondyloarthritis subtype in affected relatives influence the association between a positive family history for spondyloarthritis and HLA-B27 carriership? Results from the worldwide ASAS cohort

Background

The Assessment of SpondyloArthritis international Society (ASAS) defines a positive family history (PFH) of spondyloarthritis (SpA) as the presence of ankylosing spondylitis (AS), acute anterior uveitis (AAU), reactive arthritis (ReA), inflammatory bowel disease (IBD), and/or psoriasis in first-degree relatives (FDR) or second-degree relatives (SDR). In two European cohorts, a PFH of AS and AAU, but not other subtypes, was associated with human leukocyte antigen B27 (HLA-B27) carriership in patients suspected of axial SpA (axSpA). Because the importance of ethnicity or degree of family relationship is unknown, we investigated the influence of ethnicity, FDR, or SDR on the association between a PFH and HLA-B27 carriership in patients suspected of axSpA.

Methods

Baseline data from the ASAS cohort of patients suspected of axSpA were analyzed. Univariable analyses were performed. Each disease (AS, AAU, psoriasis, IBD, ReA) in a PFH according to the ASAS definition was a determinant in separate models with HLA-B27 carriership as outcome. Analyses were stratified for self-reported ethnicity, FDR, and SDR. Analyses were repeated in multivariable models to investigate independent associations.

Results

A total of 594 patients were analyzed (mean [SD] age 33.7 [11.7] years; 46% male; 52% HLA-B27+; 59% white, 36% Asian, 5% other). A PFH was associated with HLA-B27 carriership in patients with a white (OR, 2.3, 95% CI, 1.4–3.9) or Asian ethnicity (OR, 3.1, 95% CI, 1.6–5.8) and with a PFH in FDR (OR, 2.9, 95% CI, 1.8–4.5), but not with a PFH in SDR (OR, 1.7, 95% CI, 0.7–3.8) or in other ethnicities. A PFH of AS was positively associated with HLA-B27 carriership in all subgroups (white OR, 7.1; 95% CI, 2.9–17.1; Asian OR, 5.7; 95% CI, 2.5–13.2; FDR OR, 7.8; 95% CI, 3.8–16.0; SDR OR, 3.7; 95% CI, 1.2–11.6). A PFH of AAU, ReA, IBD, or psoriasis was never positively associated with HLA-B27 carriership. In the multivariate analysis, similar results were found.

Conclusions

In the ASAS cohort, a PFH of AS, but not of AAU, ReA, IBD, or psoriasis, was associated with HLA-B27 carriership regardless of white or Asian ethnicity or degree of family relationship. This cohort and two European cohorts show that a PFH of AS and possibly a PFH of AAU can be used to identify patients who are more likely to be HLA-B27-positive and therefore may have an increased risk of axSpA.

Frequency of Impaired Spinal Mobility in Patients with Chronic Back Pain Compared to Patients with Early Axial Spondyloarthritis

OBJECTIVE

To examine the frequency of impaired spinal mobility in patients with chronic back pain of short duration and to compare it with the frequency of impaired spinal mobility in patients with axial spondyloarthritis (axSpA), possible SpA, and no SpA.

METHODS

The SpondyloArthritis Caught Early (SPACE) cohort includes patients with chronic back pain (≥ 3 mos, ≤ 2 yrs, onset < 45 yrs). Spinal mobility was assessed with lateral spinal flexion, chest expansion, cervical rotation, occiput-to-wall distance, and lumbar flexion. Hip mobility was assessed with intermalleolar distance. Mobility measures were defined as impaired if below the 5th percentile reference curve from general population, adjusted for age and height when appropriate. Proportions of patients categorized with impaired mobility were examined with chi square.

RESULTS

In total, 393 patients with chronic back pain were included: 142 axSpA, 140 possible SpA, and 111 no SpA. Impairment in ≥ 1 mobility measure was present in 66% of all patients. The most frequently impaired mobility measure was lateral spinal flexion (40%), followed by chest expansion (22%), cervical rotation (18%), intermalleolar distance (17%), lumbar flexion (15%), and occiput-to-wall distance (11%). No statistically significant differences in proportion of patients with impaired spinal mobility were found between patients with axSpA and the other subgroups in any of the tests.

CONCLUSION

Two out of 3 patients with chronic back pain of short duration had impaired spinal mobility compared to the general population. Impaired spinal mobility occurs as often in patients with early axSpA as in other forms of chronic back pain.

Social Role Participation and Satisfaction With Life: A Study Among Patients With Ankylosing Spondylitis and Population Controls

OBJECTIVE

Participation in society of persons with chronic diseases receives increasing attention. However, little is known about which components of participation are most relevant to life satisfaction. This study examines the association between several aspects of social role participation and satisfaction with life (SWL) in patients with ankylosing spondylitis (AS) compared to population controls.

METHODS

In a cross-sectional study, participants completed the Social Role Participation Questionnaire (SRPQ) and SWL scale. The SRPQ assesses several dimensions of participation (importance, satisfaction with performance, and satisfaction with time and physical difficulty) in 11 roles representing 3 domains (interpersonal relations, leisure, and work). For individuals with AS and controls, the association between role domains and SWL was examined using linear regression for each participation dimension separately, in the total and the employed population, adjusting for age, sex, education, and income.

RESULTS

A total of 246 AS patients (mean ± SD age 51 ± 12 years, 62% males, mean ± SD disease duration 17 ± 12 years) and 510 controls (mean ± SD age 42 ± 15 years, 70% males) were included. AS patients were more frequently (extremely) dissatisfied with life (17.9% versus 8.6%; P < 0.05). In the total and the employed population, less physical difficulty and higher satisfaction with interpersonal relations and leisure were associated with higher SWL, and this was somewhat stronger in patients than in controls (P < 0.1). In employed controls, but not in employed patients, satisfaction with work was independently associated with SWL.

CONCLUSION

These findings highlight the importance of supporting persons with AS in ameliorating social role participation, particularly in areas like close relationships and leisure activities, which are typically ignored when treating AS.

2016 update of the ASAS-EULAR management recommendations for axial spondyloarthritis

To update and integrate the recommendations for ankylosing spondylitis and the recommendations for the use of tumour necrosis factor inhibitors (TNFi) in axial spondyloarthritis (axSpA) into one set applicable to the full spectrum of patients with axSpA. Following the latest version of the European League Against Rheumatism (EULAR) Standardised Operating Procedures, two systematic literature reviews first collected the evidence regarding all treatment options (pharmacological and non-pharmacological) that were published since 2009. After a discussion of the results in the steering group and presentation to the task force, overarching principles and recommendations were formulated, and consensus was obtained by informal voting. A total of 5 overarching principles and 13 recommendations were agreed on. The first three recommendations deal with personalised medicine including treatment target and monitoring. Recommendation 4 covers non-pharmacological management. Recommendation 5 describes the central role of non-steroidal anti-inflammatory drugs (NSAIDs) as first-choice drug treatment. Recommendations 6-8 define the rather modest role of analgesics, and disprove glucocorticoids and conventional synthetic disease-modifying antirheumatic drugs (DMARDs) for axSpA patents with predominant axial involvement. Recommendation 9 refers to biological DMARDs (bDMARDs) including TNFi and IL-17 inhibitors (IL-17i) for patients with high disease activity despite the use (or intolerance/contraindication) of at least two NSAIDs. In addition, they should either have an elevated C reactive protein and/or definite inflammation on MRI and/or radiographic evidence of sacroiliitis. Current practice is to start with a TNFi. Switching to another TNFi or an IL-17i is recommended in case TNFi fails (recommendation 10). Tapering, but not stopping a bDMARD, can be considered in patients in sustained remission (recommendation 11). The final two recommendations (12, 13) deal with surgery and spinal fractures. The 2016 Assessment of SpondyloArthritis international Society-EULAR recommendations provide up-to-date guidance on the management of patients with axSpA.

Is the current ASAS expert definition of a positive family history useful in identifying axial spondyloarthritis? Results from the SPACE and DESIR cohorts

Background

The Assessment of SpondyloArthritis international Society (ASAS) definition of a positive family history (PFH) of spondyloarthritis (SpA) includes the following diseases in first- or second-degree relatives: ankylosing spondylitis (AS), acute anterior uveitis (AAU), reactive arthritis (ReA), inflammatory bowel disease (IBD), and psoriasis. However, it is not known if a PFH for each of these diseases contributes to making a diagnosis of axSpA, sacroiliitis on imaging, or fulfilling the ASAS criteria in patients presenting with chronic back pain (CBP). Therefore, the aim of this study was to assess which SpA diseases in family members are associated with human leukocyte antigen B27 (HLA-B27) and axial spondyloarthritis (axSpA) in CBP patients.

Methods

CBP patients suspected of axSpA from the SPACE (n = 438) and the DESIR (n = 647) cohort were asked about the presence of SpA diseases in first- or second-degree relatives (AS, AAU, ReA, IBD, and psoriasis). The associations between a PFH and HLA-B27, sacroiliitis on imaging (magnetic resonance imaging (MRI) or radiographs), axSpA diagnosis, and ASAS classification in CBP patients were assessed.

Results

In the SPACE and the DESIR cohort, a PFH of AS (odds ratio (OR) 5.9 (95% confidence interval (CI) 3.5–9.9), and OR 3.3 (95% CI 2.1–5.2)) and a PFH of AAU (OR 9.8 (95% CI 3.3–28.9) and OR 21.6 (95% CI 2.9–160.1)) were significantly associated with presence of HLA-B27. Furthermore, in both cohorts a PFH of AS and a PFH of AAU were positively associated with fulfilment of the ASAS criteria, but not with sacroiliitis on imaging. In SPACE but not in DESIR a PFH of AAU was positively associated with axSpA diagnosis. In both cohorts a PFH of ReA, IBD, or psoriasis was not positively associated with HLA-B27 positivity, sacroiliitis on imaging, axSpA diagnosis, or meeting the ASAS criteria for axSpA.

Conclusions

In our cohorts, a PFH of AS or AAU is useful for case-finding of axSpA as this is correlated with HLA-B27 carriership. However, as a PFH of ReA, IBD, or psoriasis does not contribute to identifying axSpA in CBP patients, these data suggest that the widely used ASAS definition of a PFH of SpA should be updated.

Trial registration

Trial registration number, NCT01648907. Registered on 20 July 2012.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1335-8) contains supplementary material, which is available to authorized users.

The performance of different classification criteria sets for spondyloarthritis in the worldwide ASAS-COMOSPA study

BACKGROUND

In this study, we sought to compare the performance of spondyloarthritis (SpA) classification criteria sets in an international SpA cohort with patients included from five continents around the world.

METHODS

Data from the (ASAS) COMOrbidities in SPondyloArthritis (ASAS-COMOSPA) study were used. ASAS-COMOSPA is a multinational, cross-sectional study with consecutive patients diagnosed with SpA by rheumatologists worldwide. Patients were classified according to the European Spondyloarthropathy Study Group (ESSG), modified European Spondyloarthropathy Study Group (mESSG), Amor, modified Amor, Assessment of SpondyloArthritis international Society (ASAS) axial Spondyloarthritis (axSpA), ASAS peripheral spondyloarthritis (pSpA) and ClASsification criteria for Psoriatic Arthritis (CASPAR) criteria. Overlap between the classification criteria sets was assessed for patients with and without back pain. Furthermore, patients fulfilling different arms of the ASAS axSpA criteria (imaging arm, clinical arm, both arms) were compared on the presence of SpA features.

RESULTS

A total of 3942 patients (5 continents, 26 countries) were included. The mean age was 43.6 years, 65.0% were male, 56.2% were human leucocyte antigen B27-positive and 64.4% had radiographic sacroiliitis (based on modified New York criteria). Of the patients, 85.5% were classified by the ASAS SpA criteria (87.7% ASAS axSpA, 12.3% ASAS pSpA). Fulfilment of the Amor, ESSG and CASPAR criteria was present in 83.3%, 88.4% and 21.6% of patients, respectively. Of the patients with back pain (n = 3227), most were classified by all three of Amor, ESSG and ASAS axSpA criteria (71.4%). Patients fulfilling the imaging arm and the clinical arm of the ASAS axSpA criteria had similar presentations of SpA features. In patients without back pain, overlap between classification criteria sets was seen, although to a lesser extent.

CONCLUSIONS

Most patients with a clinical diagnosis of axial SpA in the worldwide ASAS-COMOSPA study fulfil several classification criteria sets, and a substantial overlap between different criteria sets is seen, which suggests a high level of credibility of the criteria. Large inter-regional differences in the fulfilment of classification criteria were not found. Patients fulfilling the clinical arm were remarkably similar to patients fulfilling the imaging arm with respect to the presence of most SpA features.

Is the Site of Back Pain Related to the Location of Magnetic Resonance Imaging Lesions in Patients With Chronic Back Pain? Results From the Spondyloarthritis Caught Early Cohort

OBJECTIVE

To determine associations between magnetic resonance imaging (MRI) lesions originating from either axial spondyloarthritis (SpA) or from degeneration and pain in patients with chronic back pain of <2 years duration.

METHODS

Patients from the Spondyloarthritis Caught Early (SPACE) cohort identified the sites of pain (thoracic, lumbar, buttock). The average MRI scores from 2 readers for axial SpA lesions and from 2 different readers for degenerative lesions were used. Associations between sacroiliac (SI) joint lesions and buttock pain were investigated by logistic regression analysis, and associations between axial SpA or degenerative lesions and pain in the spine (thoracic and lumbar) were investigated using generalized estimating equations. Interactions with sex, age, HLA-B27, and fulfillment of Assessment of SpondyloArthritis international Society (ASAS) criteria were tested.

RESULTS

In 348 patients (126 males, 127 fulfilling ASAS criteria, mean age 29.4 years), spinal MRI (and SI joint images in 342) were available. Pain was localized in the thoracic spine (35.9%), the lumbar spine (82.5%), or in the buttock(s) (57.8%). Inflammatory lesions of the SI joint (odds ratio [OR] 1.06; P = 0.04) and erosions of the SI joint in patients <25 years (OR 1.16; P = 0.04) were associated with buttock pain. Axial SpA spinal lesions were not associated with pain. Modic type 1 lesions in patients >35 years (OR 5.19; P = 0.001), high-intensity zone lesions in females not fulfilling ASAS criteria (OR 5.09; P = 0.001), and herniation in various subgroups (OR range 2.07-4.66) were associated with pain.

CONCLUSION

Specific degenerative lesions, but not typical axial SpA lesions, of the spine are associated with pain at the same location in some subgroups. Inflammatory lesions in the SI joint are associated with buttock pain.

Serum inflammatory biomarkers fail to identify early axial spondyloarthritis: results from the SpondyloArthritis Caught Early (SPACE) cohort

Introduction

Decreasing the diagnostic delay in axial spondyloarthritis (axSpA) remains a major challenge. Here, we assessed the value of serum inflammatory biomarkers to distinguish early axSpA from other pathologies in a large cohort of patients referred with early back pain.

Methods

Serum c reactive protein (CRP), erythrocyte sedimentation rate (ESR) and calprotectin were determined in the SPondyloArthritis Caught Early (SPACE) cohort (n=310), an early back pain inception cohort. Additionally, explorative serum biomarkers derived from the literature (interleukin-27 (IL-27), human β-defensin-2 (hBD-2) and lipcolin-2 (LCN-2)) were determined by ELISA in full-blown patients with ankylosing spondylitis (AS) (n=21) and healthy controls (n=20).

Results

Serum CRP and ESR levels were not elevated in early axSpA versus ‘control’ back pain patients. Serum calprotectin was elevated in early axSpA versus controls (p=0.01) but failed to identify early axSpA at the individual level (positive predictive value of 38.7%). As to explorative biomarkers, serum levels of IL-27 were not detectable, and hBD-2 and LCN-2 serum levels were not elevated in full-blown AS versus healthy controls (p=0.572, p=0.562, respectively). Therefore, these markers were not further determined in the SPACE cohort.

Conclusions

None of the candidate serum inflammatory markers were useful as diagnostic markers in the early phase of axSpA.

Social Role Participation in Patients With Ankylosing Spondylitis: A Cross-Sectional Comparison With Population Controls

OBJECTIVE

Participation in social roles for persons with chronic disease is important for their quality of life, but interpretation of the data on participation is difficult in the absence of a benchmark. This study aimed to compare social role participation in patients with ankylosing spondylitis (AS) to population controls using the Social Role Participation Questionnaire (SRPQ).

METHODS

There were 246 AS patients and 510 population controls who completed the SRPQ, which assesses participation in 11 roles (with scores ranging 1-5) across 4 dimensions (importance, satisfaction with performance, satisfaction with time, and physical difficulty), and additionally ranked their 3 most important roles. The ranking of role importance, the SRPQ dimension scores, and the gap between importance and satisfaction with performance of roles were compared between patients and controls.

RESULTS

Patients (62% male; mean ± SD age 51 ± 12 years) and controls (70% male; mean ± SD 42 ± 15 years) ranked intimate relationships, relationships with children/stepchildren/grandchildren, and employment as the most important roles. Compared to controls, patients gave higher scores on the SRPQ to importance (3.75 versus 3.43), but reported lower satisfaction with performance (3.19 versus 3.58) and greater physical difficulty (3.87 versus 4.67) (P ≤ 0.05 for all). The largest differences in gaps between importance and satisfaction with performance for patients compared to controls were seen in the physical leisure, hobbies, and traveling and vacation categories, in which patients assigned higher importance but reported especially low satisfaction.

CONCLUSION

As society places increasing emphasis on individual responsibility to participate fully in social roles, the current data suggest that health care providers should pay more attention to participation restrictions experienced by patients with AS.

Social Role Participation Questionnaire for patients with ankylosing spondylitis: translation into Dutch, reliability and construct validity

OBJECTIVE

The Social Role Participation Questionnaire (SRPQ) assesses the influence of health on participation in 11 specific and one general participation role across 4 participation dimensions: 'importance', 'satisfaction with time', 'satisfaction with performance' and 'physical difficulty'. This study aimed to translate the SRPQ into Dutch, and assess the clinimetric properties and aspects of its validity among patients with ankylosing spondylitis (AS).

METHODS

Translation was performed using the dual panel approach. For each participation dimension, internal consistency, test-retest reliability (n=31), and construct validity were assessed in 246 patients with AS.

RESULTS

The translation required only minor adaptations. Cronbach αs were α≥0.7. A strong correlation was present between satisfaction with 'time' and 'performance'(r=0.85). Test-retest reliability was satisfactory (κ=0.79-0.95). Correlations with participation domains of the Short-Form Health Survey 36 (SF-36), the WHO Disease Assessment Score II, and generic as well as disease-specific health outcomes (Physical and Mental component scale of the SF-36, Satisfaction With Life Scale, Bath Ankylosing Spondylitis Disease Index (BASDAI), Bath Ankylosing Spondylitis Functioning Index (BASFI)) were at least moderate (r=-0.41 to 0.75) for all dimensions except for 'role importance' where correlations were weak (r≤40). Discriminative ability across 5 self-reported health states was good for all dimensions (p<0.01). The 'general participation' role showed similar reliability and validity for each dimension, as the average of the all 11 roles.

CONCLUSIONS

The Dutch version of the SRPQ is available to help understand social role participation of patients with AS. The dimension 'role importance' measures a distinct aspect of participation. The general participation item was a good global measure of participation.

Prevalence of comorbidities and evaluation of their screening in spondyloarthritis: results of the international cross-sectional ASAS-COMOSPA study

BACKGROUND

Increased risk of some comorbidities has been reported in spondyloarthritis (SpA). Recommendations for detection/management of some of these comorbidities have been proposed, and it is known that a gap exists between these and their implementation in practice.

OBJECTIVE

To evaluate (1) the prevalence of comorbidities and risk factors in different countries worldwide, (2) the gap between available recommendations and daily practice for management of these comorbidities and (3) the prevalence of previously unknown risk factors detected as a result of the present initiative.

METHODS

Cross-sectional international study with 22 participating countries (from four continents), including 3984 patients with SpA according to the rheumatologist.

STATISTICAL ANALYSIS

The prevalence of comorbidities (cardiovascular, infection, cancer, osteoporosis and gastrointestinal) and risk factors; percentage of patients optimally monitored for comorbidities according to available recommendations and percentage of patients for whom a risk factor was detected due to this study.

RESULTS

The most frequent comorbidities were osteoporosis (13%) and gastroduodenal ulcer (11%). The most frequent risk factors were hypertension (34%), smoking (29%) and hypercholesterolaemia (27%). Substantial intercountry variability was observed for screening of comorbidities (eg, for LDL cholesterol measurement: from 8% (Taiwan) to 98% (Germany)). Systematic evaluation (eg, blood pressure (BP), cholesterol) during this study unveiled previously unknown risk factors (eg, elevated BP (14%)), emphasising the suboptimal monitoring of comorbidities.

CONCLUSIONS

A high prevalence of comorbidities in SpA has been shown. Rigorous application of systematic evaluation of comorbidities may permit earlier detection, which may ultimately result in an improved outcome of patients with SpA.

Increase in Dickkopf-1 Serum Level in Recent Spondyloarthritis. Data from the DESIR Cohort

OBJECTIVES

To investigate DKK-1 and SOST serum levels among patients with recent inflammatory back pain (IBP) fulfilling ASAS criteria for SpA and associated factors.

METHODS

The DESIR cohort is a prospective, multicenter French cohort of 708 patients with early IBP (duration >3 months and <3 years) suggestive of AxSpA. DKK-1 and SOST serum levels were assessed at baseline and were compared between the subgroup of patients fulfilling ASAS criteria for SpA (n = 486; 68.6%) and 80 healthy controls.

RESULTS

Mean SOST serum levels were lower in ASAS+ patients than healthy controls (49.21 ± 25.9 vs. 87.8 ± 26 pmol/L; p<0.0001). In multivariate analysis, age (p = 5.4 10-9), CRP level (p<0.0001) and serum DKK-1 level (p = 0.001) were associated with SOST level. Mean DKK-1 serum levels were higher in axial SpA patients than controls (30.03 ± 15.5 vs. 11.6 ± 4.2 pmol/L; p<0.0001). In multivariate analysis, DKK-1 serum levels were associated with male gender (p = 0.03), CRP level (p = 0.006), SOST serum level (p = 0.002) and presence of sacroiliitis on radiography (p = 0.05). Genetic association testing of 10 SNPs encompassing the DKK-1 locus failed to demonstrate a significant contribution of genetics to control of DKK-1 serum levels.

CONCLUSIONS

DKK-1 serum levels were increased and SOST levels were decreased among a large cohort of patients with early axial SpA compared to healthy controls. DKK-1 serum levels were mostly associated with biological inflammation and SOST serum levels.

Prevalence of degenerative changes of the spine on magnetic resonance images and radiographs in patients aged 16-45 years with chronic back pain of short duration in the Spondyloarthritis Caught Early (SPACE) cohort

OBJECTIVES

To determine the prevalence of degenerative changes (DCs) in the spine of young patients with back pain without axial spondyloarthritis (no-axSpA), with possible axSpA (poss-axSpA) and with definite axSpA (axSpA), as shown on MRI and radiographs.

METHODS

Whole-spine MRI and cervical and lumbar radiography were performed in patients ≥16 years of age with chronic back pain (≥3 months, ≤2 years, onset <45 years) and potential axSpA (Spondyloarthritis Caught Early cohort). Patients were classified as no-axSpA, poss-axSpA [not fulfilling the Assessment of Spondyloarthritis International Society (ASAS) axSpA criteria] or axSpA (fulfilling ASAS axSpA criteria). Images (MRI and X-rays) were evaluated on the presence of DCs by two independent readers, blinded to clinical and laboratory information as well as to the results of the other imaging modality. In cases of disagreement, a third reader served as adjudicator. A Chi-square test was used to analyse differences between patient groups according to various selected cut-off points (1-3) of individual DCs.

RESULTS

Of 274 patients (38% male, mean age: 29 years), 25 (9%) were classified as no-axSpA, 134 (48.9%) as poss-axSpA and 115 (42.0%) as axSpA. Two hundred and forty-five (89%) patients had DCs on MRI [21/25 (84%) no-axSpA, 121/134 (90%) poss-axSpA, 103/115 (90%) axSpA, P = 0.792], range 1-29 (median 5.5), and 121 (44%) patients had DCs on radiographs [13/25 (52%) no-axSpA, 62/134 (46%) poss-axSpA, 48/115 (42%) axSpA, P = 0.261], range 1-11 (median 2). Prevalence of DCs was similar between patient groups. DCs were predominantly found in the lumbar spine.

CONCLUSION

Prevalence of DCs was high in this cohort of young patients with short-term chronic back pain, in accordance with the literature. Prevalence of DCs in no-axSpA patients, poss-axSpA patients and axSpA patients was found to be similar.

Metric Properties of the SPARCC Score of the Sacroiliac Joints - Data from Baseline, 3-month, and 12-month Followup in the SPACE Cohort

OBJECTIVE

To evaluate metric properties of the SpondyloArthritis Research Consortium of Canada (SPARCC) score of the sacroiliac (SI) joints.

METHODS

Patients with back pain (≥ 3 months, ≤ 2 years, onset < 45 years) were included in the SPACE cohort (SpondyloArthritis Caught Early). Patients with (possible) axial spondyloarthritis had followup visits after 3 and 12 months and were treated according to clinical practice. Magnetic resonance imaging (MRI) of the SI joints (MRI-SI) was scored in 2 independent campaigns (campaign 1: at baseline and 3 months; campaign 2: at baseline, 3 months, and 12 months) by 2 different blinded reader pairs, applying the Assessment of Spondyloarthritis International Society (ASAS) definition (MRI-SI+ vs MRI-SI-; discordant cases were adjudicated by a third reader) and SPARCC score (mean of 2 agreeing readers). Calculations were made for agreement between SPARCC score cutoff values and a consensus judgment of MRI-SI+ (ASAS definition) as external standard, change in SPARCC score, and smallest detectable changes (SDC) over 3 and 12 months.

RESULTS

SPARCC score ≥ 2 showed best agreement with MRI-SI+ in both campaigns. Regarding observed changes in relation to SDC, SPARCC score changed in 70/151 patients; 26/70 patients changed > SDC (3.4), of whom 20 patients received stable treatment over 3 months in campaign 1. Over 3 months, 20/68 patients showed changes in SPARCC score; 11/20 > SDC (2.1), of whom 8 patients received stable treatment. Over 1 year, 23/74 patients changed their SPARCC score; 14/23 changed > SDC (2.4), of whom 7 received stable treatment in campaign 2.

CONCLUSION

SPARCC score ≥ 2 can be used as surrogate for a consensus judgment of MRI-SI+ (ASAS definition) in clinical trials. The SDC ranged from 2.1-3.4 dependent on reader pair and were close to the proposed minimum important change of 2.5.

Is HLA-B27 Increased in Patients Diagnosed with Undifferentiated Arthritis? Results from the Leiden Early Arthritis Cohort

Objective.

Undifferentiated arthritis (UA) is a common form of arthritis. According to the Assessment of Spondyloarthritis international Society (ASAS) criteria for peripheral spondyloarthritis (pSpA), HLA-B27 can be used to help classify patients with pSpA. We tested whether HLA-B27 is increased in patients diagnosed with UA.

Methods.

Prevalence of HLA-B27 was compared between healthy controls and patients with UA. SpA features were compared between HLA-B27-positive and -negative UA, and SpA.

Results.

We found 10.1% of UA (38/375) versus 7.2% (403/5584) of controls were HLA-B27-positive (OR 1.5, 95% CI 1.0–2.1; p = 0.037). HLA-B27-positive patients with UA had more SpA features than HLA-B27-negative patients (mean 1.6, SD 1.0, and 0.9 SD 0.6; p < 0.001), but patients with SpA had significantly more SpA features (mean 4.5, SD 1.5; p < 0.001). Family history and preceding infection were features more common in HLA-B27-positive than in HLA-B27-negative UA (15.8% vs 1.3%, p = 0.04 and 15.8% vs 2.6%, p = 0.04). After HLA-B27 testing, 21 additional patients (5.6%) with UA could potentially have been classified with pSpA according to the ASAS criteria.

Conclusion.

HLA-B27 is more common in patients with UA than in controls. However, the yield of HLA-B27 testing in UA is low. Our results suggest that HLA-B27 testing should be reserved for patients with additional SpA features.

Percentage of patients with spondyloarthritis in patients referred because of chronic back pain and performance of classification criteria: experience from the Spondyloarthritis Caught Early (SPACE) cohort

OBJECTIVES

The objectives of the study are to describe the Spondyloarthritis Caught Early (SPACE) cohort, present the performance of various SpA classification criteria and compare patients fulfilling the imaging arm with patients fulfilling the clinical arm of the Assessment of Spondyloarthritis international Society (ASAS) axSpA criteria on demographics, presence of SpA features and level of disease activity.

METHODS

Patients with back pain (≥3 months but ≤2 years, onset <45 years) visiting the rheumatology outpatient clinic of the Leiden University Medical Center were included in the SPACE cohort. Patients were classified according to the modified New York (mNY), ESSG, Amor and ASAS axSpA criteria. The sensitivity and specificity of criteria were tested against a rheumatologist's diagnosis.

RESULTS

In total, 157 patients were included; 92 patients fulfilled any criteria, 11 fulfilled the mNY (sensitivity 16.9%, specificity 100%), 68 the ESSG (sensitivity 64.6%, specificity 71.7%), 48 the Amor (sensitivity 47.7%, specificity 81.5%) and 60 the ASAS axSpA criteria (sensitivity 84.6%, specificity 94.6%). Of those 60 patients, 30 fulfilled the imaging arm and 30 the clinical arm. Patients in the imaging arm are statistically significantly more often male, have a longer symptom duration and less often a positive family history for SpA than patients fulfilling the clinical arm. Patients in both arms are very similar regarding all other SpA features and level of disease activity.

CONCLUSION

The inclusion criteria of the SPACE cohort yield the same high numbers of SpA patients compared with referral strategies like inflammatory back pain, HLA-B27+ or sacroiliitis, yet are easier to apply. The ASAS axSpA criteria outperformed the other criteria; 38.2% fulfilled the ASAS axSpA criteria. Patients fulfilling the clinical arm of the ASAS axSpA reflect a group of patients similar to those fulfilling the imaging arm.

Performance of classification criteria for peripheral spondyloarthritis and psoriatic arthritis in the Leiden Early Arthritis cohort

OBJECTIVES

The performance of spondyloarthritis (SpA) classification criteria is not well-established in general early arthritis cohorts. Therefore, the authors tested their performance in the Leiden Early Arthritis Clinic (EAC) cohort and assessed whether these criteria can assist rheumatologists in diagnosing patients.

METHODS

The authors identified all SpA and psoriatic arthritis (PsA) patients in the EAC cohort according to the diagnosis of the treating rheumatologist. A control group consisting of arthritis patients with other diagnoses was matched to the SpA and PsA patients on gender, age and symptom duration. The authors assessed the fulfilment of SpA criteria in all three groups.

RESULTS

Of the patients in the EAC cohort (n=2011), 7.5% was diagnosed with PsA and 3.8% with SpA. In the PsA group, the ClASsification criteria for Psoratic ARthritis (CASPAR) criteria had the highest sensitivity (88.7%). In the SpA group, the Assessment of SpondyloArthritis international Society (ASAS) peripheral SpA and European Spondylarthropathy Study Group (ESSG) criteria had the highest sensitivity (both 48.7%). Specificity of all criteria sets was good: ranging from 88.5% (ESSG) to 100% (Amor).

CONCLUSIONS

In early arthritis, sensitivity of SpA classification criteria is modest except for the CASPAR criteria in PsA. However, specificity of classification criteria, including the new ASAS-peripheral SpA criteria, is high.

The Devil in the Details: The Emerging Role of Anticitrulline Autoimmunity in Rheumatoid Arthritis

Rheumatoid arthritis is a chronic inflammatory autoimmune disease of unknown cause. The immune response against citrullinated Ags has recently become the prime suspect for disease pathogenesis. Immunity against citrullinated Ags is thought to play a pivotal role in the disease for several reasons: 1) citrullinated Ags are expressed in the target organ, the inflamed joint; 2) anti-citrullinated protein Abs are present before the disease becomes manifest; and 3) these Abs are highly specific for rheumatoid arthritis. In this review, data from clinical, genetic, biochemical, and animal studies is combined to create a profile of this remarkable autoantibody response. Moreover, a model is proposed of how the anti-citrullinated proteins response is generated and how it could eventually lead to chronic inflammation.